Researchers have generally regarded the 20,000-mile-wide (32,000 kilometers) hexagon — a jet stream composed of air moving at about 200 mph (320 km/h) — as a lower-atmosphere phenomenon, restricted to the clouds of Saturn's troposphere. But the bizarre structure actually extends about 180 miles (300 km) above those cloud tops, up into the stratosphere, at least during the northern spring and summer, a new study suggests.